Japan's ruling party marked its 50th anniversary Tuesday with a proposed constitutional change that could give the nation a more assertive international military presence.

The pacifist constitution's first alteration since its adoption in 1947 would create an official role for the Japanese armed forces. The language of the revision would then allow those forces to assist military allies and help with armed international peacekeeping, according to outside experts and members of the ruling Liberal Democratic Party.

Japan maintains a small domestic self-defense force under the current constitution, which renounces war and bars the country from using military force in international disputes.

The government put forth an interpretation in 1992 that allowed troops to have noncombat roles in international peacekeeping operations. About 500 non-combat troops are helping with reconstruction in Iraq and a contingent of ships is giving logistical support to anti-terror operations in Afghanistan.

The proposed revision by the LDP, which has ruled Japan almost continuously since its founding in 1955, still renounces war but allows the nation to use its armed forces for self-defense and international peacekeeping.

"In addition to activities needed for self defense," the draft says, "the defense forces can take part in efforts to maintain international peace and security under international cooperation."

Party members and outside observers said that provision could allow armed peacekeeping and joint military efforts with allies such as the United States.

The change is part of a general push by Prime Minister Junichiro Koizumi's government to give Japan a larger military and diplomatic profile. The LDP also has long campaigned to completely replace the constitution, which was drafted by U.S. military occupiers after World War II.

Koizumi, addressing party loyalists assembled at a Tokyo hotel, credited his ruling party with guiding Japan through a half-century of peace and prosperity.

The prime minister urged Japan to match its status as the world's second-biggest economy with more cooperation with the international community.

"We need to take up the challenges of strife and conflict that may face international society over the next 50 years," Koizumi said.

Any constitutional change must be approved by two-thirds majorities in both houses of parliament and a majority of the population in a national referendum. No timetable has been set for the draft's presentation to the parliament.

The LDP draft also weakens provisions on the separation of church and state, saying public institutions may engage in religious activity "within the boundary of social rituals and customary activities." Critics say a change could give the prime minister greater freedom to make inflammatory visits to a war shrine opposed by Asian countries that suffered under Japan's wartime aggression.

Tokyo's relations with Beijing and Seoul have become strained in recent months over Koizumi's repeated visits to the Yasukuni shrine, which commemorates Japan's war dead. Critics say the visits glorify militarism.

The present charter bans the state from religious activity.